Immune Responses Against SARS-CoV-2 WT and Delta Variant in Elderly BNT162b2 Vaccinees

• Published in: Frontiers in immunology 2022-06, Vol.13, p.868361-868361
• Main Authors: Jäger, Michael, Sonnleitner, Sissy Therese, Dichtl, Stefanie, Lafon, Eliott, Diem, Gabriel, Walder, Gernot, Lass-Flörl, Cornelia, Wilflingseder, Doris, Posch, Wilfried
• Format: Article
• Language: English
• Subjects: Age-dependent immune responses after BNT162b2; Immunology; neutralizing antibodies; SARS-CoV-2; SARS-CoV-2 vaccination; T cell immunity; variants of concern (VOCs)
• ISSN: 1664-3224; 1664-3224
• DOI: 10.3389/fimmu.2022.868361

BackgroundResidents of nursing homes are one of the most vulnerable groups during the severe acute syndrome coronavirus 2 (SARS-CoV-2) pandemic. The aim of this study was to characterize cellular and humoral immune responses in >70-year-old participants before vaccination, after first and second vaccination with BNT162b2, in contrast to second-dose-vaccinated participants younger than 60 years. MethodsPeripheral blood mononuclear cells of 45 elderly and 40 younger vaccinees were analyzed by IFNγ ELISpot, specific immunoglobulin G antibody titers against SARS-CoV-2 spike protein, and neutralization abilities against SARS-CoV-2 wild-type (WT) and Delta variant (B.1.617.2). ResultsOur results clearly demonstrate a significantly increased T cell response, IgG titers, and neutralization activities against SARS-CoV-2 WT and Delta between first and second vaccination with BNT162b2 in elderly vaccinees, thereby highlighting the importance of the second booster. Interestingly, similar cellular and humoral immune responses against SARS-CoV-2 WT and Delta were found after the second vaccine dose in the young and elderly groups. ConclusionsOur data demonstrate a full picture of cellular and humoral immune responses of BNT162b2-vaccinees in two age cohorts. In all vaccines, SARS-CoV-2 WT-specific antibodies with similar neutralizing activity were detected in all vaccinees. After the second vaccination, neutralization titers against SARS-CoV-2 Delta were impaired in both age groups compared with SARS-CoV-2 WT, thereby emphasizing the need for an additional booster to overcome rising variants of SARS-CoV-2.